Yet, it's the 49ers and Chargers playing for their playoff lives against each other Thursday, hoping to keep pace with the Missouri franchises, who face off in St. Louis Sunday -- the winner in St. Louis remaining atop its respective division.

How the AFC and NFC Wests will be won will come down to attrition of who is the best of teams that wouldn't challenge in any other division. Consider that the AFC South is the only other division being contested by a team near the .500 mark (the Colts at 7-6). But the competitive balance of the western divisions has provided a pretty captivating race to the finish line.

"We're very thankful to be in this situation and to have our guys be excited about the opportunity that's in front of us," 49ers coach Mike Singletary said.

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The 49ers have won five of their last eight, surviving an 0-5 start and the firing of offensive coordinator Jimmy Raye after three games. The 49ers (5-8) are just one game back of the NFC West-leading Rams (6-7) who currently hold the tie breaker over the Seahawks (6-7).

Meanwhile, the Chargers are hoping to close the season the way they typically do, with a rally that creates distance between them and the rest of the typically woeful AFC West. Problem is, the Chargers trail the Chiefs (8-5) by a game, and the division is not as sorry as usual with the Raiders very much alive, in part, because of a 28-13 beatdown administered to the Chargers two weeks ago that wrapped up a season sweep.

That hiccup placed more importance on Thursday's game against the 49ers, who have even more at stake. A loss and San Francisco is all but out of it -- but not completely.

"Obviously San Diego has been in that situation the last few years and somehow, at this time of year, they ignite," Singletary said. "We have to go through them in order to get where we want to go. That is a tremendous challenge."

Singletary has tied his team's, and maybe his own, fate to quarterback Alex Smith. Blind faith was placed in Smith entering the season, and he couldn't deliver. He wasn't the only problem, but he was heavily blamed until a shoulder injury opened the door for Troy Smith, who led the 49ers' resurrection with three victories. Even though he won more than Alex Smith, things weren't headed in the direction the coaching staff had hoped.

In a surprise gamble -- although with Singletary, nothing should be viewed as a surprise -- he replaced Troy Smith with Alex Smith last week against division-rival Seattle. Troy Smith got them off the mat, but his limitations with the knowledge of the system become a handicap.

Alex Smith delivered, throwing three touchdowns in a 40-21 rout over the Seahawks. He will start against the Chargers, but Singletary wouldn't guarantee him another start beyond Thursday.

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"I'm just taking it a game at a time and so is he," Singletary said. "Some things the last couple of weeks happened that I felt it wasn't fair to the offensive staff, it wasn't fair to the offensive players, and it wasn't fair to Troy. If we have to do it again we'll do it again, but we have a guy in Alex Smith that is working his tail off.

"Troy went in and busts his tail to learn as fast as he can, and what he did for those five weeks was a blessing. I just felt that going back to Alex was more true to where we are, and it could really show what we have in terms of being able to utilize all of our weapons, being able to change plays at the line of scrimmage and all of those little things."

The 49ers and Chargers won last week after losses that could have -- in just about every other division would have -- ended their playoff hopes. Both teams received help, but the Chargers did themselves a favor by beating the Matt Cassel-less Chiefs.

The 49ers were kept afloat by the Rams and Seahawks losing. Rams general manager Billy Devaney told me before his team lost to the Saints on Sunday that the game wasn't a make-or-break, but that he would be doing some scoreboard watching. After the loss, players and coaches understood the importance of this meeting with the Chiefs.

This is the first meaningful game the Rams have played against Kansas City in years. The winner greatly helps its cause while inflicting damage to the cross-state foe. Should the Chiefs win, they assure themselves a winning record for the first time since 2006, when, at 9-7, they were a wild card behind the Chargers.

A winning season without the playoffs won't be good enough, really.

Chiefs coach Todd Haley told me last week that they're still in the "foundation building" process, but slipping out of contention at this point would have nothing to do with building, but dismantling what they've pieced together thus far. It hasn't been determined if Cassel will be healthy enough to play against the Rams, but based on a conversation I had with someone close to the situation, I'd expect him to give it a try.

The Rams, meanwhile, are putting a lot of emphasis on this game. While much of what they've done just to win six game has exceeded expectations and talent, they want the division title.

Otherwise, why would it be scoreboard watching?

At some point, some teams are going to win the AFC and NFC West, even if it's by default.